Moderate hypofractionated helical tomotherapy for localized prostate cancer: preliminary report of an observational prospective study

Objective: To report preliminary findings of a phase II study exploring the clinical outcomes of moderate hypofractionated radiotherapy performed with helical tomotherapy (HT) using computed tomography-magnetic resonance imaging-based planning for localized prostate cancer. Methods: The phase II prospective study received ethics approval from our institutional ethics committee. A dose of 60 Gy/20 fractions for low-intermediate risk prostate cancer by means of HT was explored. Primary endpoints of the study were acute and late gastrointestinal (GI) and genitourinary (GU) toxicities. Secondary endpoints were quality of life and biochemical-free survival. Results: A total of 35 patients were included in this interim report. At the time of the analysis, median follow-up was 36 months (range, 13-62). Acute GI toxicity was recorded as follows: grade 1 in 34% and grade 2 in 14%; acute GU toxicity was grade 1 in 71% and grade 2 in 11%. For the entire population of the study, no acute toxicities > grade 3 occurred. A single case of late grade 3 GU toxicity was registered, whereas no late GI toxicity > grade 3 was recorded. At the time of the final assessment, no biochemical failure was detected. Conclusions: The preliminary results of the present phase II trial, using HT for moderate hypofractionation in localized prostate cancer, are optimal. In fact, HT guaranteed an acceptable tolerability profile with low rates of GU and GI side effects and, more specifically, no acute severe adverse events were recorded. Long-term findings are warranted.